no longer depend on mysterious fast boot flag

index.js

@@ -5,12 +5,15 @@ const path = require('path');
 const filterInitializers = require('fastboot-filter-initializers');
 const VersionChecker = require('ember-cli-version-checker');
 const mergeTrees = require('broccoli-merge-trees');
+const semver = require('semver');
 
 module.exports = {
   name: 'ember-cli-head',
 
   treeForApp(defaultTree) {
-    if (!process.env.FASTBOOT_NEW_BUILD) {
+    let fastboot = this.project.findAddonByName('ember-cli-fastboot');
+
+    if (fastboot && semver.gte(fastboot.pkg.version, '1.0.0-rc.1')) {
       let trees = [defaultTree];
 
       if (!this.hasGlimmer2()) {

package.json

@@ -51,7 +51,8 @@
     "ember-cli-babel": "^6.0.0",
     "ember-cli-htmlbars": "^1.3.0",
     "ember-cli-version-checker": "^1.1.6",
-    "fastboot-filter-initializers": "^0.0.2"
+    "fastboot-filter-initializers": "^0.0.2",
+    "semver": "^5.3.0"
   },
   "engines": {
     "node": ">= 4"

yarn.lock

@@ -4835,10 +4835,14 @@ semver@^4.1.0, semver@^4.3.1:
   version "4.3.6"
   resolved "https://registry.yarnpkg.com/semver/-/semver-4.3.6.tgz#300bc6e0e86374f7ba61068b5b1ecd57fc6532da"
 
-semver@^5.1.0, semver@^5.1.1, semver@^5.3.0:
+semver@^5.1.0, semver@^5.1.1:
   version "5.3.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
 
+semver@^5.3.0:
+  version "5.3.0"
+  resolved "https://registry.npmjs.org/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
+
 send@0.15.1:
   version "0.15.1"
   resolved "https://registry.yarnpkg.com/send/-/send-0.15.1.tgz#8a02354c26e6f5cca700065f5f0cdeba90ec7b5f"